1. Technical Field
The present invention relates to methods for connecting substrates and methods for manufacturing semiconductor devices.
2. Related Art
In recent years, electronic equipment often use FPC (Flexible Printed Circuit: Flexible substrate) as a method for electrically connecting electronic components to be provided on the electronic equipment. Amid advancing miniaturization of electronic equipment which require installation of electronic components in a small space, FPCs are more often used as electronic components can be laid out within a small space of electronic equipment while freely bending highly flexible FPCs. However, for further miniaturization of electronic equipment and application of FPCs to electronic devices, FPCs that can provide controllable bent shapes are in greater demand.
In this connection, Japanese Laid-open Patent Application 2002-171031 (Patent Document 1) proposes a FPC equipped with portions that can be readily bent, which are formed with a plurality of through holes, in other words, perforations, at bending portions in the FPC. Also, Japanese Laid-open Patent Application 2006-140452 (Patent Document 2) describes a structure to prevent a cover film from peeling from a resin base film, in which metal wires at bending portions are made thinner to increase bonding areas between the base film and the cover film, which uses the property of adhesive in which the adhesive force of the adhesive bonding the cover film to the resin base film is greater than to the metal wires.
However, both of the references Patent Documents 1 and 2 described above involve an independent bending step of bending a FPC, and pertain to readiness of bending the FPC and prevention of damage to the FPC. In particular, according to Patent Document 1, perforations need to be formed in advance in a FPC, which results in a longer manufacturing process, and thus a higher cost.